The Lunar Laser Communications Demonstration (LLCD)

Boroson, Don M.; Scozzafava, Joseph J.; Murphy, Daniel V.; Robinson, Bryan S.; Lincoln, M. I. T.

doi:10.1109/smc-it.2009.57

Cited by 82 publications

(29 citation statements)

References 6 publications

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“…Photon detection occurs when a single quantum of light is absorbed and triggers a transition from the superconducting to the normal state. SSPDs have high efficiency, low jitter, low dark count rate and fast reset time [2], and are therefore a key technology for, among others, quantum key distribution [3], interplanetary communication [4] and cancer research [5].…”

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confidence: 99%

Position-Dependent Local Detection Efficiency in a Nanowire Superconducting Single-Photon Detector

et al. 2015

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We probe the local detection efficiency in a nanowire superconducting single-photon detector along the cross-section of the wire with a spatial resolution of 10 nm. We experimentally find a strong variation in the local detection efficiency of the device. We demonstrate that this effect explains previously observed variations in NbN detector efficiency as function of device geometry.Nanowire superconducting single-photon detectors (SSPDs) consist of a superconducting wire of nanoscale cross-section [1], typically 4 nm by 100 nm. Photon detection occurs when a single quantum of light is absorbed and triggers a transition from the superconducting to the normal state. SSPDs have high efficiency, low jitter, low dark count rate and fast reset time [2], and are therefore a key technology for, among others, quantum key distribution Although progress has been made recently, the underlying physical mechanism responsible for photon detection on the nanoscale is still under active investigation. A combination of theory [6,7], experiments [8][9][10] and simulations [11,12] on NbN SSPDs indicates that the absorption of a photon destroys Cooper pairs in the superconductor and creates a localized cloud of quasiparticles that diverts current across the wire. This makes the wire susceptible to the entry of a superconducting vortex from the edge of the wire. Energy dissipation by this moving vortex drives the system to the normal state.An important and unexpected implication of this detection model is a nanoscale position variation in the photodetection properties of the device. The conditions at the entry point of the vortex determine the energy required for it to cross the wire. This causes photons absorbed close to the edge to have a local detection efficiency (LDE) [13] compared to photons absorbed in the center of the wire [12]. This effect has practical implications for the operation of SSPDs, since it represents a potential limitation of the detection efficiency. In addition, SSPDs have been proposed for nanoscale sensing, either in a near-field optical microscope configuration [14] or as a subwavelength multiphoton probe [15], where this effect would be of major importance for the properties of such a microscope. While this effect has been predicted theoretically, clear experimental evidence is missing. * renema@physics.leidenuniv.nlIn this work, we experimentally explore the nanoscale variations in the intrinsic response of the detector. We spatially resolve the LDE with a resolution of approximately 10 nm, better than λ/50, using far-field illumination only. We find that our results are qualitatively consistent with numerical simulations [11,12]. Our results provide excellent quantitative agreement with experiments that indicate a polarization dependence in the LDE that was hitherto not understood [16].The key technique used in this work is a differential polarization measurement that probes the IDE of the detector (see Figure 1). The technique is based on the fact that polarized light is absorbed preferentially in dif...

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confidence: 99%

Position-Dependent Local Detection Efficiency in a Nanowire Superconducting Single-Photon Detector

et al. 2015

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“…For the LLCD experiment [1] the OGS was modified to serve as a complementary ground station. To allow communication with the LADEE spacecraft different subsystems at the ESA OGS had to be modified.…”

Section: System Overviewmentioning

confidence: 99%

Ground receiver unit for optical communication between LADEE spacecraft and ESA ground station

et al. 2014

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NASA's Lunar Laser Communication Demonstration (LLCD) demonstrates optical communication between ground stations on Earth and NASA's LADEE spacecraft orbiting the Moon. As a contribution to the LLCD experiment, the European Space Agency (ESA) prepares its existing optical ground station to serve as a complementary ground communication terminal. A ground receiver unit was developed for this purpose. It comprises optical detectors and electronics to recover the frames, decode the data and store them in a large data buffer.The overall ground receiver unit design is presented and explained together with ground test activities. Different optical detectors had been evaluated and two detector types were chosen for implementation. A multimode fiber is used to couple the optical signal from the existing telescope into the detectors. The 16ary-Pulse Position Modulation (PPM) signal is then processed in the electronics. Clock recovery and frame synchronization could be shown to work reliably at low power and under severe power fluctuations. For error correction, a powerful ½-rate Serially Concatenated PPM (SCPPM) decoder is applied. The user data is decoded at a throughput of 39Mbps with up to 20 turbo iterations. With the developed ground receiver unit an average signal power of only a few hundred picowatts is required to yield a frame error rate smaller than 10 -5 .

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“…Erbium doped fibers (EDFs) based devices are widely employed in space for optical communication [1], remote sensing [2], and navigation applications, e.g. interferometric fiber optic gyroscope (IFOG).…”

Section: Iintroductionmentioning

confidence: 99%

Radiation hardening commercial off-the-shelf erbium doped fibers by optimal photo-annealing source

Peng

Liu

Lin

et al. 2017

International Conference on Space Optics — ICSO 2016

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The Lunar Laser Communications Demonstration (LLCD)

Cited by 82 publications

References 6 publications

Position-Dependent Local Detection Efficiency in a Nanowire Superconducting Single-Photon Detector

Position-Dependent Local Detection Efficiency in a Nanowire Superconducting Single-Photon Detector

Ground receiver unit for optical communication between LADEE spacecraft and ESA ground station

Radiation hardening commercial off-the-shelf erbium doped fibers by optimal photo-annealing source

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